feat(testing): add more parser tests
feat(testing): add more parser tests

Add more parser tests including a negative test for bad
charges (`Na+Cl-`).

Signed-off-by: Jeremy A Gray <240a8bde05828aaf6570efdac484e7686c640004@gmail.com>

bjodah/aqchem,bjodah/chempy,bjodah/aqchem,bjodah/chempy,bjodah/aqchem